In general, various efforts for reducing the vehicle weight and improving safety during a collision have been exerted in an automobile industry.
A hot stamping technology using a boron steel plate has been actively developed in order to satisfy both weight and rigidity of the vehicle body.
The hot stamping technology is a method of heating (900° C. to 950° C.) the boron steel plate in a separate heating furnace, press forming the heated steel plate, and then rapidly cooling the press formed steel plate in a mold to manufacture a high strength component of 1500 MPa or more through a phase transformation to martensite.
A method of first cold forming a boron steel plate, heating (900° C. to 950° C.) the formed steel plate in a separate heating furnace, and then rapidly cooling the heated steel plate in a separate cooling mold to manufacture a vehicle body component having high strength of 1500 MPa or more through a phase transformation to martensite is also used.
However, an installation space is limited in the hot stamping technology because the heating furnace having a length of about 25 m is necessarily installed, and the manufacturing time of the hot stamping technology is excessively taken because the steel plate before forming or the formed steel plate is heated while passing through the heating furnace.
Further, since the heating operation and the cooling operation of the steel plate are performed in the separate heating furnace, the cost is unnecessarily consumed.
The aforementioned drawbacks cause degradation of general productivity of the high strength component.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.